The present invention relates to a copolymer, possessing superior adhesion properties with respect to surfaces comprising a high polarity, such as metal surfaces and the like, which effectively imparts both hydrophobic and thermal resistance properties, exhibits a favorable solubility in solvents used for manufacturing paints, resists, and the like, and contains only small amounts of insoluble matter; a manufacturing method for the same; and a resist composition using the same. The present application is based on Japanese Patent Application No. Hei 10-82186, Japanese Patent Application No. Hei 10-82187, Japanese Patent Application No. Hei 10-82188, and Japanese Patent Application No. Hei 11-66615, the contents of which are incorporated herein by reference.
Hitherto, it is known that a compound possessing a high polarity imparts superior adhesion properties to surfaces possessing an equally high polarity, such as metal surfaces, due to their electrostatic interaction. On the other hand, it is known that a compound possessing a low polarity is superior with respect to its hydrophobic properties; and also that a cyclic compound is superior with respect to the thermal resistance properties imparted.
Thus, in order to provide a paint which exhibits superior adhesion properties to surfaces possessing a high polarity, e.g., metal surfaces and the like, and which can also impart both hydrophobic and thermal resistance properties effectively, a binary copolymer has been proposed, as a resin composition for paints, which is formed by means of polymerizing a monomer comprising a high polarity, and monomer comprising a low polarity, which contains a cyclic structure.
However, when polymerizing monomers comprising significantly different polarities, one of which contains a large cyclic structure, due to the large differences in their monomer reactivity, great difficulty is encountered at the time of attempting random polymerization. Hence, such reactions are likely to yield a copolymer wherein the majority of only one type of monomer component is polymerized during the initial stages of polymerization, followed by polymerization of the majority of the other type of monomer during the later stages of polymerization. As a result, when dissolving such a copolymer in a solvent used for manufacturing solvent paints or resist compositions, due to the solubility of a portion of the copolymer, which the content of the monomer components greatly lies to either of the monomer components, is unfavorable, a insoluble matter in the solvent is generate. This insoluble matter in the solvent, in turn, results in clogging of the filters during the filtration process for paints and the like, and produces an undesirable external appearance for the final coating.
Accordingly, it is an object of the present invention to provide a copolymer obtained by means of polymerizing a monomer comprising a high polarity, which imparts superior adhesion properties to surfaces possessing a high polarity, e.g., metal surfaces and the like; and a monomer comprising a low polarity in addition to cyclic structure, which effectively imparts both hydrophobic and thermal resistance properties; a method for manufacturing the same; and a resist composition using the same. The copolymer of the present invention exhibits a favorable solubility in solvents, and contains only a small amount of insoluble matter, when used for paints or resist compositions.
In addition, another object of the present invention is to provide a resist resin possessing a superior transparency with respect to an ArF excimer laser (at a wavelength of 193 nm).
In consideration of the aforementioned objects, as a result of intense research with respect to the solubility of various copolymers, the inventors of the present invention have found that it is possible to provide a copolymer obtained by means of polymerizing a monomer comprising a low polarity and a cyclic structure, and a monomer comprising a high polarity, which can exhibit a favorable solubility in solvents for paints, resists, and the like, and which is free of insoluble matter. The aforementioned characteristics are obtained by means of (1) keeping the copolymer composition of said monomer comprising a high polarity, which has varied depending on the copolymer chain, within a specific range approximating the average copolymer composition of said monomer comprising a high polarity in the entire copolymer; (2) adding a monomer comprising a specific polarity to the polymerization; and (3) manufacturing said copolymer according to a particular polymerization method.
In other words, the copolymer according to the present invention is a copolymer obtained by means of polymerizing at least a monomer containing an alicyclic structure, and a monomer containing a lactone structure, wherein the distribution of the copolymer composition of said monomer containing a lactone structure is within xe2x88x9210 to +10 mol % of the average copolymer composition of said monomer containing a lactone structure in the entire copolymer.
In addition, the copolymer according to the present invention is a copolymer obtained by means of polymerizing a monomer containing an alicyclic structure, a monomer containing a lactone structure, and another vinyl monomer, wherein said other vinyl monomer possesses a higher polarity than said monomer containing an alicyclic structure, but a lower polarity than said monomer containing a lactone structure.
In addition, the copolymer according to the present invention preferably possesses a 193 nm light transmittance of 60% or greater when measured at a film thickness of 500 nm.
The method for manufacturing the copolymer according to the present invention is characterized in comprising the step of adding dropwise a mixed solution comprising monomer components containing at least a monomer containing an alicyclic structure, and a monomer containing a lactone structure; a polymerization initiator; and a solvent, to a solvent which has been heated to a polymerization temperature.
Furthermore, the resist composition according to the present invention is characterized in comprising said copolymer according to the present invention.
In addition, said monomer containing an alicyclic structure preferably comprises at least one monomer selected from among the group consisting of cyclohexyl(meth)acrylate, isobornyl(meth)acrylate, adamantyl(meth)acrylate, tricyclodecanyl(meth)acrylate, dicyclopentadienyl(meth)acrylate, and substitution products thereof.
In addition, said monomer containing a lactone structure preferably comprises at least one monomer selected from among the group consisting of substituted and unsubstituted (meth)acrylates containing a xcex4-valerolactone ring, and substituted and unsubstituted monomers containing a xcex3-butyrolactone ring.
The copolymer according to the present invention exhibits superior adhesion properties to surfaces possessing a high polarity, such as metal surfaces and the like, in addition to excellent hydrophobic and thermal resistance properties, and also displays a favorable solubility in solvents used for paints, and resists, and the like.
In addition, the copolymer possessing a 193 nm light transmittance of 60% or greater, measured at a film thickness of 500 nm, exhibits a superior transparency with respect to an ArF excimer laser (with a wavelength of 193 nm), and thus is preferred as an ArF resist resin.
In addition, by means of using said monomer containing a particular alicyclic structure, it is possible to improve both the hydrophobic and thermal resistance properties of the copolymer.
In addition, by means of using said monomer containing a particular lactone structure, it is possible to improve the adhesion properties of the copolymer.
In addition, according to the method for manufacturing the copolymer of the present invention, it is possible to provide a copolymer which exhibits superior adhesion properties to surfaces possessing a high polarity, such as metal surfaces and the like, in addition to excellent hydrophobic and thermal resistance properties, and also exhibits a favorable solubility in solvents used for paints, resists, and the like.
In addition, the resist composition according to the present invention is superior with respect to uniformity, sensitivity, and resolution.